1. Field
This application relates to a solar powered transmitter comprising an antenna and provides methods for operating and adjusting the transmitter. The transmitter can be used to transmit a control field for providing a containment area for vehicles, such as shopping carts.
2. Description of Related Art
Motorized and/or non-motorized (e.g., human-propelled) vehicles are used in a wide range of applications. In some of these applications, it may be desirable to provide a vehicle containment system that can be used to inhibit or prevent the vehicle from moving into or out of a containment area. The containment area may include or demarcate an unsafe or undesirable region for vehicle movement or a region in which the vehicle should be confined. In one illustrative example, a shopping cart containment system can be used to deter theft of shopping carts from a retail location such as, e.g., a supermarket.
In some implementations, a boundary of the containment area is marked, and movement of the vehicle across the boundary triggers the containment system to inhibit or prevent movement of the vehicle. In some such implementations, the boundary of the containment area can be marked, for example, by using a buried wire cable that transmits an electromagnetic control signal, by placing or embedding magnets at the boundary, or by broadcasting an electromagnetic control signal from a wireless access point.
In some embodiments suitable for human-propelled vehicles (e.g., carts), a wheel brake mechanism is disposed in or on one or more wheels of the cart. When the cart is moved across the boundary, a sensor in the cart (e.g., in the wheel) detects the control signal, and in response, the wheel brake mechanism is actuated and inhibits the wheel from rotating (e.g., the wheel may lock or be difficult to turn). Such a system advantageously deters theft (and/or inhibits movement of carts into undesirable and/or unsafe areas), because a user will have to drag (or carry) the cart once the wheel has locked. An authorized attendant can use a handheld remote control, a key, or other unlocking mechanism to unlock the wheel, thereby permitting the cart to be rolled back to the retail location.